Global Patent Index - EP 0913980 A3

EP 0913980 A3 2001-04-25 - Protection of active telephone line interface circuits

Title (en)

Protection of active telephone line interface circuits

Title (de)

Schutzanordnung für eine aktive Fernsprechsleitungsschnittstellenschaltung

Title (fr)

Protection des circuits d'interface actifs des lignes téléphoniques

Publication

EP 0913980 A3 (EN)

Application

EP 98310260 A

Priority

  • EP 95910378 A
  • US 31893194 A

Abstract (en)

[origin: WO9611543A1] A telephone line interface circuit with d.c. amplifiers (12) coupled to tip and ring paths is protected against transient voltages by a crowbar-type protection device (52) coupled via a diode bridge (28, 30) to the tip and ring paths, positive and negative terminals of the diode bridge being connected respectively to ground and via a diode (54) to a negative supply voltage line for the amplifiers. The diode prevents discharge of a capacitor (26), coupled between the negative supply voltage line and ground, through the protection device when it conducts. A locked up state, in which the amplifiers maintain holding current to the protection device after a transient voltage, is avoided by further diodes (56, 58) coupled from the negative terminal of the diode bridge to inputs of the amplifiers, or by controlling a current limiter (34) to interrupt current to the capacitor when the diode is reverse biased, so that the capacitor discharges. The current limiter includes a resistance (38) and inductance (40) in series for sensing current, whereby initial charging current for the capacitor is reduced on closing of relay contacts (K1, K2) in series with the current limiter, and relay contact deterioration is avoided.

IPC 1-7 (main, further and additional classification)

H04M 3/18; H02H 9/04

IPC 8 full level (invention and additional information)

H02H 9/04 (2006.01); H04M 3/18 (2006.01); H04Q 3/42 (2006.01)

CPC (invention and additional information)

H04M 3/18 (2013.01); H02H 9/048 (2013.01); H04M 2201/80 (2013.01)

Citation (search report)

Designated contracting state (EPC)

DE FR GB

EPO simple patent family

WO 9611543 A1 19960418; CA 2159273 A1 19960407; CA 2159273 C 19980421; DE 69513190 D1 19991209; DE 69513190 T2 20000309; DE 69530131 D1 20030430; DE 69530131 T2 20030911; EP 0784896 A1 19970723; EP 0784896 B1 19991103; EP 0913980 A2 19990506; EP 0913980 A3 20010425; EP 0913980 B1 20030326; JP 3313726 B2 20020812; JP H10507059 A 19980707; US 5539820 A 19960723

INPADOC legal status


2005-01-07 [REG FR ST] NOTIFICATION OF LAPSE

2004-11-30 [PG25 FR] LAPSED IN A CONTRACTING STATE ANNOUNCED VIA POSTGRANT INFORM. FROM NAT. OFFICE TO EPO

- Ref Country Code: FR

- Free text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

- Effective date: 20041130

2004-10-27 [GBPC] GB: EUROPEAN PATENT CEASED THROUGH NON-PAYMENT OF RENEWAL FEE

2004-10-01 [PG25 DE] LAPSED IN A CONTRACTING STATE ANNOUNCED VIA POSTGRANT INFORM. FROM NAT. OFFICE TO EPO

- Ref Country Code: DE

- Free text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

- Effective date: 20041001

2004-03-17 [26N] NO OPPOSITION FILED

- Effective date: 20031230

2004-03-08 [PG25 GB] LAPSED IN A CONTRACTING STATE ANNOUNCED VIA POSTGRANT INFORM. FROM NAT. OFFICE TO EPO

- Ref Country Code: GB

- Free text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

- Effective date: 20040308

2003-11-28 [ET] FR: TRANSLATION FILED

2003-10-08 [RAP2] TRANSFER OF RIGHTS OF AN EP GRANTED PATENT

- Owner name: NORTEL NETWORKS LIMITED

2003-04-30 [REF] CORRESPONDS TO:

- Document: DE 69530131 P 20030430

2003-03-26 [AC] DIVISIONAL APPLICATION (ART. 76) OF:

- Document: EP 0784896 P

2003-03-26 [AK] DESIGNATED CONTRACTING STATES:

- Designated State(s): DE FR GB

2003-03-26 [AX] REQUEST FOR EXTENSION OF THE EUROPEAN PATENT TO

- Countries: AL LT LV MK RO SI

2003-03-26 [REG GB FG4D] EUROPEAN PATENT GRANTED

2001-12-19 [17P] REQUEST FOR EXAMINATION FILED

- Effective date: 20011025

2001-04-25 [AK] DESIGNATED CONTRACTING STATES:

- Kind Code of Ref Document: A3

- Designated State(s): DE FR GB

2001-04-25 [AX] REQUEST FOR EXTENSION OF THE EUROPEAN PATENT TO

- Free text: AL PAYMENT 19990115;LT PAYMENT 19990115;LV PAYMENT 19990115;MK PAYMENT 19990115;RO PAYMENT 19990115;SI PAYMENT 19990115

2001-04-25 [RIC1] CLASSIFICATION (CORRECTION)

- Free text: 7H 04M 3/18 A, 7H 02H 9/04 B

2000-09-27 [RAP1] TRANSFER OF RIGHTS OF AN EP PUBLISHED APPLICATION

- Owner name: NORTEL NETWORKS LIMITED

1999-07-14 [RAP3] CORRECTION OF THE ADDRESS OR NAME OF APPLICANT (A DOCUMENT)

- Owner name: NORTEL NETWORKS CORPORATION

1999-05-06 [AC] DIVISIONAL APPLICATION (ART. 76) OF:

- Document: EP 784896

1999-05-06 [AK] DESIGNATED CONTRACTING STATES:

- Kind Code of Ref Document: A2

- Designated State(s): DE FR GB

1999-05-06 [AX] REQUEST FOR EXTENSION OF THE EUROPEAN PATENT TO

- Free text: AL PAYMENT 19990115;LT PAYMENT 19990115;LV PAYMENT 19990115;MK PAYMENT 19990115;RO PAYMENT 19990115;SI PAYMENT 19990115